There is a lot at stake in the Korea summit, which comes amid questions about whether Kim will keep his promise to close his main nuclear testing facility and end the North's missile program.

CIA Director Mike Pompeo with North Korean leader Kim Jong Un in early April 2018.
White House

Chinese scientists maintain that North Korea's main nuclear testing facility, buried deep in the mountains, has been so damaged by previous tests that it's no longer usable, which makes Kim's promise to close it ring hollow. But recent satellite imagery shows ongoing activity and many U.S. experts believe the site is still operational.

Mistrust of the North runs deep.

"I think we really need to double check what he is saying," said retired South Korean Lt. General In Bum Chun. "Does he really mean that he is going to give up all of this?"

The Korean War split apart thousands of families when the fighting stopped in 1953. Il Young Yoon is hoping the summit will allow him to reunite with his older brother who was trapped on the northern side of the border. He hasn't seen him in 68 years.

"I don't even know if he is dead or alive," he said. "I would like to see him before I die."

An adviser to South Korean President Moon Jae-in says the South hopes to create a road map for North Korea to give up its weapons and also lay the groundwork for the expected meeting between Kim and President Trump, which could happen next month.